Four trials are carried out to measure the time taken for a pendulum to complete 10 oscillations, and the results are recorded in the table below:
TrialTime taken (s)115.4215.6315.1415.5 \begin{array}{|c|c|} \hline \text{Trial} & \text{Time taken (s)} \\ \hline 1 & 15.4 \\ \hline 2 & 15.6 \\ \hline 3 & 15.1 \\ \hline 4 & 15.5 \\ \hline \end{array} Trial1234Time taken (s)15.415.615.115.5What is the mean time taken for the pendulum to complete the oscillations?
15.1 s15.1\text{ s}15.1 s
15.4 s15.4\text{ s}15.4 s
15.5 s15.5\text{ s}15.5 s
61.6 s61.6\text{ s}61.6 s